PHP - Bitwise XOR operator

The Bitwise XOR operator (^) is a binary operator which takes two bit patterns of equal length and performs the logical exclusive OR operation on each pair of corresponding bits. It returns 1 if only one of the bits is 1, else returns 0.

Bit_1Bit_2Bit_1 ^ Bit_2
000
101
011
110

The example below describes how bitwise XOR operator works:

50 ^ 25 returns 43

50    ->    110010  (In Binary)
^ 25    ->  ^ 011001  (In Binary)
----        --------
43    <-    101011  (In Binary)

The code of using Bitwise XOR operator (^) is given below:

<?php
\$x = 50;
\$y = 25;
\$z;

//Bitwise XOR operation
\$z = \$x ^ \$y;

//Displaying the result
echo "z = \$z";
?>

The output of the above code will be:

z = 43

Example: Swap two numbers without using temporary variable

The bitwise XOR operator can be used to swap the value of two variables. Consider the example below.

<?php
function swap(\$x, \$y) {
echo "Before Swap.\n";
echo "x = \$x \n";
echo "y = \$y \n";

//Swap technique
\$x = \$x ^ \$y;
\$y = \$x ^ \$y;
\$x = \$x ^ \$y;

echo "After Swap.\n";
echo "x = \$x \n";
echo "y = \$y \n";
}

swap(10, 25);
?>

The above code will give the following output:

Before Swap.
x = 10
y = 25
After Swap.
x = 25
y = 10

❮ PHP - Operators

5